WO1999002586A1

WO1999002586A1 - Prepreg fabric and honeycomb sandwich panel

Info

Publication number: WO1999002586A1
Application number: PCT/JP1998/003095
Authority: WO
Inventors: Hajime Kishi; Masahiko Hayashi; Toshiaki Higashi
Original assignee: Toray Industries, Inc.
Priority date: 1997-07-11
Filing date: 1998-07-10
Publication date: 1999-01-21
Also published as: JP3661194B2; EP0927737A1; DE69834800T2; DE69834800D1; EP0927737B1; US6429157B1; EP0927737A4

Abstract

A prepreg fabric at least comprising [A] a reinforcing fabric, [B] a thermosetting resin or a thermosetting resin composition and [C] fine resin particles, which is characterized by having a cover factor of 95 % or above; and a sandwich panel characterized by comprising skin panels made from the prepreg fabric and [D] a honeycomb core. The prepreg fabric is little changed in the tack as prepreg after the lapse of time, has suitable drape properties (flexibility) and exhibits excellent self-bondability to ahoneycomb core when used as the skin panel of a honeycomb sandwich panel, and the honeycomb sandwich panel is advantageous in that the skin panels made of a product of curing of the prepreg fabric have a lowered inner porosity and that the skin panels have few holes and depressions on their surfaces and are thus excellent in surface smoothness.

Description

Woven prepreg and 82 cam sandwich panel

TECHNICAL FIELD The present invention relates to a woven pre-predator and a honeycomb sandwich panel. In more detail, tack (adhesiveness) as a pre-predator A woven prepreg that has little change over time, has an appropriate drape property (flexibility), and has excellent self-adhesiveness to the honeycomb core when used as a skin panel of a honeycomb sandwich panel The present invention relates to an eighty-two-cam sandwich panel which has a low porosity inside a skin panel made of a cured product of a pre-preda and has few holes and depressions on the surface of the skin panel and excellent surface smoothness. Background art

Conventionally, fiber-reinforced composite materials composed of reinforcing fibers and matrix resin have been widely used in aircraft, automobiles, and industrial applications due to their excellent mechanical properties. In recent years, the properties required for fiber-reinforced composite materials have become more and more strict as their use has increased. It is important to reduce the defects that lead to a reduction in strength in order to fully exploit the mechanical properties and durability of fiber-reinforced composite materials. In particular, in the case of aircraft structural materials and interior materials, the use of fiber reinforced composite materials as skin panels for honeycomb sandwich panels is increasing from the viewpoint of weight reduction. Honeycomb cores include aramide honeycomb and aluminum honeycomb.In particular, a so-called cocure composition in which a prepreg is laminated on both sides of a honeycomb core made of aramide paper, and curing of the prepreg itself and bonding of the prepredder and the honeycomb core simultaneously. It is common practice to manufacture honeycomb sandwich panels depending on the shape. Here, the adhesive strength between the 82 cam core and the pre-predator laminate as a skin panel is important. Conventionally, a film-like adhesive is sandwiched between the honeycomb core and the pre-predator laminate to cure the pre-predator and simultaneously In addition, a method of curing a sandwich panel has also been frequently used. However, honeycomb sandwich panels From the standpoint of further weight reduction and molding cost reduction, it has been recently required to directly bond the honeycomb and the pre-preda without using a film-like adhesive (hereinafter referred to as self-adhesiveness).

However, when bonding without using a film-like adhesive, there is no resin equivalent to the resin in the film-like adhesive. Therefore, the resin contained in the prepreg instead of the film-like adhesive has the 82-cam core side. The honeycomb wall had to move during molding to sufficiently wet the honeycomb wall, and it was difficult to achieve high adhesive strength. The part where the resin drips from the prepredder laminate in the thickness direction of the honeycomb core along the wall of the 82-cam or is cured in a raised state is called a fillet. The fillet is formed by the honeycomb core and the upper and lower skin panels. It is difficult to form them sufficiently between them. If the viscosity of the resin is too low, the resin tends to flow down along the 82-cam wall from the upper skin panel, and as a result, the bonding strength between the upper skin panel and the honeycomb core is insufficient. On the other hand, if the resin viscosity is too high, the resin cannot sufficiently wet the honeycomb wall, and in particular, the adhesive strength between the lower skin panel and the honeycomb core tends to be insufficient.

On the other hand, since the resin contained in the pre-preda must be distributed to the honeycomb core wall side, there is a problem that the absolute amount of the resin in the laminate is insufficient and porosity is easily formed in the skin panel. In the case of a honeycomb sandwich panel, porosity is more likely to be generated than in the case of forming a normal prepreg laminate, since pressure is not applied to the pre-preders in the upper and lower portions of the hexagonal cavity of the honeycomb core during the forming.

Conventionally, in order to reduce defects such as pits and resin fading on the skin panel surface, a method of applying a film-like adhesive to the surface of the prepreg laminate and curing it together with the prepreg has been used frequently. From the viewpoint of further reducing the weight of the honeycomb sandwich panel and reducing the material and molding costs, it is more desirable to be able to mold a skin panel that is smooth and free from surface defects without using a film-like adhesive.

However, if a film-like adhesive is not used, there is no resin equivalent to the resin in the adhesive film, so the resin remaining on the skin panel surface is relatively small, and it is impossible to achieve a high-quality surface condition. It was a difficult task.

Pre-predator using carbon fiber as reinforcing fiber for use in honeycomb molding The following is a conventional technique relating to the matrix resin. U.S. Pat. No. 4,500,660 discloses that dicyandiamide is added to a reaction product of a specific epoxy resin, a butadiene acrylonitrile copolymer having functional groups at both ends, and an epoxy resin. An epoxy resin composition is disclosed. The purpose is to improve the self-adhesion between the prepreg and the honeycomb and the interlaminar shear strength of the skin panel. However, the U.S. patent does not aim at improving the surface smoothness of the skin panel, does not have sufficient heat resistance as compared with the present invention because of the curing agent used, and contains resin fine particles in the resin composition. Therefore, the object of the present invention is not achieved.

Japanese Patent Application Laid-Open No. 58-82,755 describes that a reaction product of an epoxy resin, a liquid butadiene acrylonitrile copolymer having a carboxyl group at both ends and an epoxy resin is treated with dicyandiamide as a curing agent. The use of a composition in which a combination of diamine and diaminodiphenyl sulfone is used, the self-adhesiveness between the pre-preda and the honeycomb core, especially at high temperatures, must be increased, and no defects should occur on the surface of the honeycomb panel. The purpose is described. However, the Japanese Unexamined Patent Publication does not describe at all how to suppress the secular change as a pre-predator, and does not achieve the object of the present invention because the resin composition does not contain fine resin particles. Also, US Pat. No. 5,557,831 describes an effect of using a resin having high thixotropy for a woven pre-preda for a honeycomb cure to reduce porosity inside a skin panel. However, in the US patent, resin particles are not blended in the resin composition, and the self-adhesion between the pre-preda and the honeycomb core is poor.

On the other hand, when using a pre-predator, the tackiness (adhesiveness) and drape (suppleness) of the pre-preda are often problematic. These properties greatly affect the workability when handling the pre-preda.

If the tackiness of the pre-preda is too small, the pre-preda, which has been pressed down repeatedly in the pre-preda lamination process, will immediately peel off, which will hinder the lamination work. In such a case, it is necessary to increase the working environment temperature until a proper tackiness is obtained. Conversely, if the tackiness of the pre-preda is too great, If it does, it will stick due to the weight of the pre-predator, making it difficult to remove and correct it later.

Also, if the drape property of the pre-preda is poor, the lamination work is significantly reduced due to the rigidity of the pre-preda, and the laminated pre-preda does not exactly follow the curved surface of the mold or the shape of the mandrel, and becomes wrinkled or the reinforcing fiber is broken. Defective parts will occur. In such cases, it is necessary to raise the working environment temperature, but it is difficult to balance with tackiness, and these are very serious problems in the molding operation.

The tackiness and drapability of these pre-predas are mainly governed by the viscoelasticity of the matrix resin, but in general, the viscoelasticity of the epoxy resin has a large temperature dependence, and if the temperature of the working environment fluctuates, the adhesiveness The drapability changes, and in some cases the work becomes impossible.

Furthermore, immediately after the prepreg is made, even if it has a moderate tackiness due to the presence of a relatively large amount of resin on the surface, the resin gradually sinks into the interior over time and the tackiness gradually decreases. It tends to be impossible to perform lamination work under the same conditions, which is a serious problem for industrial materials. When the resin viscosity is relatively high, there is a tendency that the change over time in the aging property is small, but on the other hand, the drapability tends to be insufficient.

Epoxy resin compositions containing a high molecular weight epoxy resin have been developed in order to improve the molding workability by optimizing the pre-predator's setting and drape properties. It is disclosed in Japanese Unexamined Patent Publication (Kokai) and JP-A-63-38026. In addition, Japanese Patent Application Laid-Open No. 2-254646 discloses an epoxy resin composition containing a nitrile rubber-modified epoxy resin for the purpose of optimizing drapability and resin flow. However, even if these techniques can improve either the tackiness or the drapability of the pre-predator, the balance between them is not appropriate and the mechanical properties of the obtained molded body are sacrificed. Had inconvenience.

As a technique for improving the tackiness of a prepredder, it is known that a high molecular compound such as a thermoplastic resin or an elastomer is mixed with an epoxy resin. For example, Japanese Unexamined Patent Publication No. Sho 58-87224 and Japanese Unexamined Patent Publication No. Sho 62-169824 JP-A-55-27342, JP-A-55-108443, JP-A-56-219 A method of adding a polyvinyl acetate resin disclosed in JP-A-52-18787, a method of adding a polyvinyl butyral resin disclosed in JP-A-52-18787, There is known a method of blending a polyester polyurethane disclosed in Japanese Patent Application Laid-Open No. HEI 11-135, a method of blending a polyvinyl ether disclosed in Japanese Patent Application Laid-Open No. H11-156156, and the like.

However, such a method has a restriction that the viscosity of the resin increases and the drapability deteriorates, and it has been difficult to find a resin having both satisfactory tackiness and drapability.

In other words, it is difficult to obtain a woven pre-predder that has good physical properties, especially self-adhesiveness required for honeycomb cure, maintains appropriate tackiness without change over time, and has sufficient drapability with the conventional technology. there were.

The techniques disclosed in the above-mentioned known examples do not have sufficient self-adhesiveness between the skin panel and the 82 cam core, or do not aim at reducing the porosity in the skin panel, and do not describe the effects thereof. . In addition, the surface smoothness when the prepreg is laminated and cured as the skin panel surface itself without using an adhesive film on the outside of the prepreg as the skin panel of the honeycomb sandwich panel is known. The technique disclosed in the examples was not sufficient. Furthermore, there is no technology that can improve the tackiness and drapability of a woven prepreg and reduce its aging. In other words, the self-adhesion between the skin panel and the honeycomb core is improved, the porosity in the skin panel is reduced, the surface smoothness is improved when the skin panel is made of a honeycomb sandwich body, and the time-dependent suppression of tackiness as a pre-predator is improved. However, it was extremely difficult to design a pre-preda that satisfies all good drape characteristics. Disclosure of the invention

The present invention is excellent in self-adhesiveness to the honeycomb and porosity reduction properties in the skin panel, furthermore, reduces the defects on the surface of the honeycomb sandwich skin panel and keeps the proper tackiness as a prepreg without changing over time, thereby improving the drapability. Excellent textile pre The purpose is to provide a Preda.

The molded product obtained by curing the woven pre-preda of the present invention has high heat resistance, toughness and impact resistance, and can be used as an excellent structural material.

In order to achieve the object of the present invention, the present invention has the following configuration.

That is, it is a woven pre-predder comprising at least the following [A], [B] and [C] and having a cover factor of 95% or more.

[A] Reinforced fiber fabric

[B] Thermosetting resin or thermosetting resin composition

[C] Resin fine particles

Furthermore, there is provided a honeycomb sandwich panel comprising at least the following skin panels [A], [B] and [C] and [D].

[A3 Reinforced fiber fabric

[B] Thermosetting resin or thermosetting resin composition

[C] Resin fine particles

[D] Honeycomb core

The cover factor of a woven prepreg is the ratio of the existing area of the yarn portion to the total area of the prepreg. The better the weave is spread, the higher the coverage factor. By using a woven pre-preda with a cover factor of 95% or more as a skin panel, the porosity, which is a defect inside the skin panel, is reduced, resulting in a skin panel with excellent rigidity and strength. Evaluated by the climbing drum peel method It is possible to obtain a honeycomb sandwich panel having excellent self-adhesiveness between a skin panel and a honeycomb core to be formed and having excellent surface smoothness of the skin panel. In addition, it is easy to keep the resin on the prepreg surface, and the tack aging of the prepreg is less likely to change over time. If the cover factor is insufficient, pits tend to be formed on the surface of the skin panel of the molded body, and porosity tends to be generated inside the skin panel. Also, if the cover factor is large, a molded plate having excellent burn-through characteristics and good fire resistance can be obtained. A particularly suitable cover factor range for the present invention is 96% or more, and more preferably 97.5% or more. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

In the present invention, [A] is a reinforced fiber woven fabric.

As the reinforcing fiber, glass fiber, carbon fiber, aramide fiber, boron fiber, alumina fiber, silicon carbide fiber, and the like are used. These fibers may be used as a mixture of two or more kinds. In order to obtain a lighter and more durable molded product, it is particularly preferable to use carbon fiber or graphite fiber. From the viewpoint of the intrinsic tensile strength of the fiber divided by the high impact resistance of a honeycomb sandwich panel, a high-strength carbon fiber having a strand tensile strength of 4.4 GPa or more and a tensile elongation at break of 1.7% or more is more preferable. From the viewpoint of improving impact resistance, it is particularly preferable to use carbon fiber having a tensile elongation of 1.7% or more, a tensile modulus E of 200 GPa or more, and a fracture strain energy of 4.0 mm-kgf / mm ³ It is preferable that it is above. Use of a reinforcing fiber having a high tensile modulus E leads to obtaining high strength in the climbing drum peel method, which is one of the self-adhesiveness evaluations. Examples of such high-strength, high-elongation carbon fibers include T700SC, T800H, and T1000G manufactured by Toray Industries, Inc. A conventionally known two-dimensional fabric can be used as the reinforcing fiber fabric. As the weave structure, weaves such as plain weave, twill weave, entangled weave and waxy weave are preferred. In particular, it is suitable for easily forming compacts with a thin plain weave structure. The woven yarn of the woven fabric is composed of fiber bundles, and the number of filaments in one fiber bundle is preferably in the range of 2500 to 30,000. If the number is less than 2500, the fiber arrangement tends to meander, which tends to cause a decrease in strength. On the other hand, when the number is more than 3,000,000, resin impregnation hardly occurs at the time of preparing or molding the pre-preda. More preferably, it is in the range of 2800 to 25,000. In particular, those having 5000 to 25,000 filaments are preferred from the viewpoint of improving the surface smoothness of the honeycomb skin panel.

Similarly, the fineness of the fiber bundle is preferably from 1500 to 20,000 denier. If it is less than 1,500 denier, the fiber arrangement tends to meander, and if it is more than 20,000 denier, resin impregnation is less likely to occur during the preparation or molding of the pre-preda.

Flat carbon fiber multifilament that is substantially twisted and composed of multiple carbon fibers The use of woven fabrics with woven yarns reduces the aging of the prepreg's tackiness because the movement of the woven fibers is less likely to sink into the surface resin even if the woven pre-preda is left for a long time. Is preferred. Also, the movement of the woven fiber is small and the sink of the surface resin hardly occurs even in the pre-predator during the molding, so that the surface smoothness of the cured honeycomb sandwich panel is improved, which is preferable. here

“Substantially no twist” means that there is no more than one turn of twist per lm of yarn length. In particular, a woven fabric comprising a multifilament yarn having substantially no twist in the multifilament yarn and having a bunching property in a hook-drop value of 100 to 100 mm, preferably 100 to 500 mm. It is preferable to use woven fiber from the viewpoints of reducing the movement of the woven fiber, keeping the flat state of the yarn easily, suppressing the change in tack of the pre-preder with time, and improving the surface smoothness of the honeycomb sandwich panel. The twist-twist reduces the hook drop value.

In the case of reinforcing fabrics using carbon fiber yarns, carbon fibers are generally entangled with the filaments of the fiber bundle of the precursor in order to prevent process troubles caused by winding wound filaments around rollers in the manufacturing process. Bundling property is given to carbon fiber yarn. In addition, the carbon fiber yarns are given bunching properties by the amount of sizing agent attached and the adhesion between filaments. The convergence is controlled by the degree of entanglement between filaments, the amount of sizing agent attached and the degree of adhesion. If the hook drop value is 100 mm or less and the convergence is too strong, it is difficult to increase the covering factor of the woven fabric or the cover factor of the pre-preda described later, and the effect of suppressing the temporal change of the tackiness of the pre-preda decreases. In addition, the resin impregnating property of the pre-preda tends to be poor. As a result, surface pits and internal voids of the skin panel are likely to occur. If the hook drop value is more than 100 mm, the convergence of the carbon fiber yarn is deteriorated, the fluff is likely to be generated, the weaving property is deteriorated, and the strength of the composite material is reduced.

Carbon fiber multifilament yarns are flat, Itoatsumi is 0. 0 5 to 0. 2 mm, yarn width / Itoatsumi ratio of 3 0 or more, the fabric weight per unit area is 1 0 0~3 2 0 g / m 2 It is preferable to use a woven fabric because crimping is kept small, movement of the woven fiber is made small, and the resin in the pre-predator after resin impregnation is hardly moved, and the time-dependent change in tackiness is suppressed. In addition, by using such flat woven yarn, the fiber density is higher than that of ordinary woven fabric. It is preferable because a woven fabric can be obtained and the surface smoothness of the 82-cam sandwich panel can be improved. In addition, the use of a flat yarn increases the rigidity of the skin panel, reduces the porosity, which is an internal defect, and achieves high strength in the climbing drum peel method, which is one of the self-adhesion evaluation methods. To A thickness of 0.15 to 0.35 mm as the woven pre-preda is preferable from the viewpoint of improving the surface smoothness of the honeycomb sandwich panel because the unevenness due to the bending of the woven yarn does not substantially occur. The woven fabric using the flat carbon fiber multifilament yarn as described above can be produced, for example, by a method described in Japanese Patent Application Laid-Open No. 7-30739.

In the present invention, the resin content in the prepreg or the skin panel is preferably in the range of 33 to 50% by weight. When the resin content is 33% by weight or less, the pre-predder tends to have poor adhesiveness, and surface pits on the skin panel and resin faintness, and porosity in the skin panel are easily generated, and self-adhesiveness to the honeycomb core is reduced. descend. Also, if the resin content exceeds 50% by weight, there is a concern that resin outflow is likely to occur at the time of preparing a pre-predator or at the time of molding, and the advantage of weight reduction is reduced because the weight of the molded body increases. Particularly preferably, the resin content is in the range of 35 to 45% by weight.

In the present invention, [B] is a thermosetting resin or a thermosetting resin composition. Here, the thermosetting resin is not particularly limited as long as it is a resin that is cured by heat or external energy such as light or an electron beam to at least partially form a three-dimensional cured product. Preferred thermosetting resins include an epoxy resin, a phenol resin, a vinyl ester resin, an unsaturated polyester resin, a cyanate resin, a maleimide resin, and a polyimide resin.

An epoxy resin is preferably used as the thermosetting resin.

Particularly, an epoxy resin using an amine, a phenol, or a compound having a carbon-carbon double bond as a precursor is preferable.

Specifically, examples of the dalicidylamine-type epoxy resin using amines as a precursor include various isomers of tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol and triglycidylaminocresol. Tetraglycidyldiaminodiphenylmethane is preferred as a resin for composite materials as an aircraft structural material because of its excellent heat resistance. A glycidyl ether type epoxy resin using phenol as a precursor is also preferable. Bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin, cresol nopolak epoxy resin, and resorcinol epoxy resin.

Among these, it is preferable to use a dalicidyl ether type epoxy resin having an epoxy equivalent of 400 or more, since the self-adhesiveness between the skin panel obtained by curing the pre-preda and the honeycomb core becomes high.

Liquid bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and resorcinol-type epoxy resin have low viscosities and are therefore preferable for compounding other epoxy resins and additives.

Solid bisphenol A-type epoxy resin gives a structure with a lower crosslink density compared to liquid bisphenol A-type epoxy resin, thus lowering heat resistance.However, it is preferable to mix appropriately to obtain a structure with higher toughness. Used. In particular, it has the effect of improving the self-adhesiveness between the skin panel and the honeycomb core, and suppressing the aging of the tackiness of the pre-predator, and increasing the surface viscosity by increasing the resin viscosity and securing the surface resin of the panel. Therefore, it is preferable.

An epoxy resin having a naphthalene skeleton is preferable because it gives a cured resin having low water absorption and high heat resistance. Also, a biphenyl-type epoxy resin, a dicyclopentene-type epoxy resin, and a diphenylfluorene-type epoxy resin are suitably used because they give a cured resin having a low water absorption. Urethane-modified epoxy resins and isocyanate-modified epoxy resins are preferred because they give cured resins with high fracture toughness and high elongation.

These epoxy resins may be used alone, or may be appropriately blended and used. It is preferable to mix at least a bifunctional epoxy resin and a trifunctional or higher functional epoxy resin in order to provide both fluidity of the resin and heat resistance after curing. In particular, a combination of a daricidylamine epoxy and a daricidyl ether epoxy is preferable because it enables both heat resistance, water resistance, and processability. It is also preferable to mix at least one kind of epoxy resin which is liquid at room temperature and one kind of epoxy resin which is solid at room temperature in order to make the tackiness and drape property of the pre-predeer appropriate. Phenol nopolak epoxy resin and cresol nopolak epoxy resin Since heat resistance is high and water absorption is small, it is preferable to provide a resin having high heat and water resistance. By blending these, the tackiness and drape of the pre-preda can be adjusted while improving the heat resistance and water resistance.

As a curing agent for the epoxy resin, any compound having an active group capable of reacting with an epoxy group can be used. Preferably, a compound having an amino group, an acid anhydride group, or an azide group is suitable. More specifically, for example, dicyandiamide, various isomers of diaminodiphenylmethanediaminodiphenylsulfone, aminobenzoic acid esters, various acid anhydrides, phenol novolak resin, cresol nopolak resin, polyphenol compound, imidazo Carboxylic acid anhydrides such as methyl derivatives, aliphatic amides, tetramethyldanidine, thiourea-added amines, methylhexahydrophthalic anhydride, carboxylic acid hydrazides, carboxylic acid amides, polymer carbane, and trifluoride. Lewis acid complexes such as boron ethylamine complex are exemplified. When aromatic diamine is used as a curing agent, an epoxy resin cured product having good heat resistance can be obtained. In particular, various isomers of diaminodiphenyl sulfone are most suitable for obtaining a cured product having good heat resistance. The addition amount is preferably stoichiometrically equivalent, but depending on the case, it is preferable to use, for example, an equivalent ratio of around 0.7 to 0.8 since a high elastic modulus resin can be obtained. These curing agents may be used alone or in combination. It is also preferable to use a combination of dicyandiamide and a urea compound, for example, 3,4-dichlorophenyl-1,1-dimethylperyl, or an imidazole as a curing agent, since high heat and water resistance can be obtained while curing at a relatively low temperature. . Curing with an acid anhydride is preferable because it gives a cured product having a lower water absorption than curing with an amine compound. In addition, it is preferable to use a latent material of these curing agents, for example, a microencapsulated one, because the storage stability of the pre-preda, particularly tackiness and drapeability, hardly changes even at room temperature.

Further, an epoxy resin and a curing agent, or a product obtained by preliminarily reacting a part of the epoxy resin and the curing agent, can be blended in the composition. This method may be effective for adjusting viscosity and improving storage stability.

A phenol resin is also preferably used as the thermosetting resin.

Phenol resin has high flame retardancy and is preferred as interior material / building material. Especially aircraft interiors As a material, 82-cam sandwich panels are preferred because they are light-weight and have high strength and high rigidity.However, if phenolic resin is used as the matrix resin for the skin panel, it will have excellent flame retardancy and low smoke emission in case of fire. Used favorably.

In general, thermosetting phenolic resins include various phenols such as alkyl phenols such as phenol and cresol propyl xylenol, and halogenated alkyl phenols in which a part of the benzene ring of the alkyl phenol is substituted with a halogen atom. And aldehydes such as formaldehyde, acetoaldehyde, and furfural. Thermosetting phenolic resins are broadly classified into two types depending on the catalyst used during their synthesis. One is a nopolak-type phenolic resin synthesized using an acidic catalyst, and the other is a resolving resin synthesized using a basic catalyst. Phenolic resin, but both can be used in the present invention. The novolak type phenol resin requires an amide-based curing agent such as hexamethylenetetramine as a catalyst for heat curing, but the resol type phenol resin hardens only by heating. If an acid catalyst is added, the resole-type phenol resin can be cured at a lower temperature. Further, an ammonia resol type phenol resin and a benzoxazine type phenol resin are also preferable. The benzoxazine-type phenolic resin is a resin having an oxazine ring synthesized from phenols, aldehydes, and amines. Since it is cured by ring-opening polymerization, condensed water is not generated and voids are not easily generated in the molded product. Therefore, a high-strength molded body is easily obtained, which is preferable. If bisphenol is selected as the phenol, it is bifunctional, so that the crosslinking density is increased and the heat resistance is improved. Various structures such as bisphenol A, bisphenol F, bisphenol S, biphenyl, dihydroxybenzophenone, and diphenylfluorene can be used as the raw material bisphenol. Polycyclic phenols such as naphthol and naphthodiol can also be used as raw materials.

The phenolic resin is often dissolved or dispersed in a solvent or water, but is preferably used in the present invention because the higher the solid content concentration, the less a void is formed in a molded product. In particular, those having a solid content of 70% by weight or more, more preferably 80% by weight or more are preferable.

As the thermosetting resin, a cyanate resin is also preferably used.

Cyanate resin is represented by bisphenol and phenol novolac Is a cyanate ester of a polyhydric phenol. Generally, it has better heat resistance and lower water absorption rate than epoxy resin, so it is preferable when characteristics in high temperature state of water absorption are important.

As the thermosetting resin, a maleimide resin having an average of two or more maleimide groups in the molecule is also preferable since it has good heat resistance.

In addition, polyimide resin and resin having vinyl group and aryl group, for example, vinyl ester resin and unsaturated polyester resin can be used as [B].

It is preferable to use a thermosetting resin composition in which the glass transition temperature (Tg) of the cured resin is 160 ° C. or more, since sufficient heat resistance can be imparted to the honeycomb sandwich panel.

Furthermore, various modifiers can be added to the thermosetting resin in order to improve the viscoelasticity of the uncured resin and the rigidity and toughness of the cured resin. Specifically, one or more additives selected from solid rubber, liquid rubber, thermoplastic resin elastomer, thermoplastic resin, inorganic particles, short fibers and the like are preferably used.

In general, solid rubber has a large increase in viscosity when the same amount is dissolved in epoxy resin compared to liquid rubber, and maintains the heat resistance of the molded product relatively while maintaining the resin composition at an appropriate viscosity level during the molding process It is preferable because it is possible. Reduces the temperature dependence of the viscoelastic function of the resin composition, makes it difficult to handle even if the working environment temperature changes when handling the pre-predator, and reduces the time-dependent change in tackiness due to leaving the pre-predator unattended. Improve the surface smoothness of certain skin panels. As the solid rubber, an acrylonitrile-butadiene copolymer, which is a random copolymer of butadiene and acrylonitrile, is preferred from the viewpoint of compatibility with the epoxy resin. The compatibility with the epoxy resin can be controlled by changing the copolymerization ratio of acrylonitrile. Further, a solid rubber having a functional group is more preferable in order to increase the adhesiveness with the epoxy resin. Examples of the functional group include a carboxyl group and an amino group. Particularly, solid acrylonitrile-butadiene rubber containing a carboxyl group is preferable. Also, nitrile hydride is preferable because of its excellent weather resistance. NI POL 1 072, NI POL 1072 J, NI POL 1472, NI POL 1472 HV, NIPOL 10042, NIP〇L 1 043, NIP OL DN 631, NIPO L 1001 ZETPOL 220, ZETPOL 220, ZETPOL 3110 (all manufactured by Nippon Zeon Co., Ltd.) and the like.

The rubber has a functional group and reacts with the epoxy group during mixing with the epoxy resin to form some high molecular weight and a branched structure. It is preferable to increase the surface smoothness of the panel. In particular, when such a preliminary reaction is positively used, the amount of addition required to provide excellent surface smoothness and effectively suppress the change with time of the tack of the pre-predator may be smaller than when the preliminary reaction is not performed. . For example, if the pre-reaction is not intended, the solid rubber and epoxy resin can be pre-reacted under heating while the tackiness of the pre-predator and the surface smoothness of the molded plate can be achieved by adding 7% by weight of solid rubber. For example, it can be achieved by adding about 3% by weight of solid rubber. The preliminary reaction is usually carried out by mixing under heating, and it is preferable to carry out mixing at a temperature of 70 or more at a temperature of 30 minutes or more, since this is effective for improving the surface smoothness and suppressing the secular change over time. More preferably, the mixing is carried out at a temperature of 70 or more for 1 hour or more. However, if the pre-reaction is carried out too much, the resin viscosity becomes too high, which may be disadvantageous for processes required for prepreg production such as film formation and fiber impregnation. Therefore, more preferred pre-reaction conditions are mixing at a temperature in the range of 70-85 ° C for 1-3 hours. When pre-reacting the solid rubber with the epoxy resin, it is preferable to first react with the epoxy resin having a small number of functional groups as an epoxy resin, and then mix with a epoxy group having a large number of functional groups, for example, a tetrafunctional epoxy, because the degree of thickening can be easily controlled. No. For the same reason, the epoxy resin having four or more functional groups preferably accounts for 60% or less of the epoxy composition.

It is also preferable to add inorganic particles as a modifier for the thermosetting resin. Examples include talc, aluminum silicate, particulate silica, calcium carbonate, myriki, montmorillonite, smectite, carbon black, silicon carbide, and alumina hydrate. These inorganic particles have a large rheological control, that is, a thickening effect and a thixotropic property-imparting effect. Among them, particulate silica is known to have a large thixotropic effect when added to a resin composition, but it also reduces the temperature dependence of the viscoelastic function of the resin composition and reduces Deterioration of handleability can be prevented even when the working environment temperature fluctuates. In addition, the time-dependent change in tackiness due to pre-preda It is preferable because it improves the surface smoothness of the skin panel, which is a cured product, and gives an effect of excellent self-adhesion to the honeycomb core.

As fine-particle silica having silicon dioxide as a basic skeleton, for example, those having an average primary particle size in the range of 5 to 40 nm are commercially available under the trademark of AEROSIL (manufactured by Nippon AEROSIL Co., Ltd.). It is preferable that the primary particle diameter is as small as 40 nm or less, since this gives a sufficient thickening effect. The particle size is evaluated with an electron microscope. The specific surface area is preferably in the range of 50 to 400 m ² / g. Generally, silica whose silica surface is covered with a silanol group is used.However, it is not possible to use hydrophobic particulate silica in which the hydrogen of the silanol group is substituted with a methyl group, an octyl group, dimethylsiloxane, or the like. It is more preferable from the viewpoint of the thickening effect of the resin, the stabilization of thixotropy, and the improvement of mechanical properties represented by water resistance and compressive strength of the molded product.

When a solid rubber is used as the modifier, it is preferable to add it in the range of 1 to 10% by weight based on the whole resin composition. If the content is less than 1% by weight, the tackiness of the pre-preda is poor, and pits and resin faint easily occur on the skin panel surface of the honeycomb sandwich panel. On the other hand, if it exceeds 10% by weight, the resin viscosity is too high, and it becomes difficult to impregnate the prepreg. A more preferable addition amount is in a range of 2 to 6% by weight, and further preferably a range of 2 to 4% by weight.

When inorganic particles are added as a modifier, it is preferable to add them in the range of 0.8 to 8% by weight based on the whole resin composition. If the amount is less than 0.8% by weight, pits and resin faintness are likely to occur on the skin panel surface of the honeycomb sandwich panel, while if the amount is more than 8% by weight, the resin viscosity is too high and impregnation into the prepreg tends to be difficult. A more preferable addition amount is in a range of 0.8 to 5% by weight, and further preferably a range of 1 to 3% by weight. The solid rubber and the inorganic particles may be used alone, but the combined use is more preferable for reducing the pits on the skin panel surface, improving the tackiness of the pre-preda, suppressing the change over time and maintaining the heat resistance of the molded product. In that case, the most preferable addition amount is in the range of 2 to 4% by weight of the solid rubber and 1 to 3% by weight of the inorganic particles.

It is also preferable to add a thermoplastic elastomer as a modifier. In particular, polyester-based or polyamide-based thermoplastic elastomers are preferably blended. Epoxy resin blended with polyester or polyamide thermoplastic elastomer The composition has excellent tackiness, low viscosity, and excellent drapability and impregnation into reinforcing fibers. In addition, the temperature dependence of the viscoelastic function of the resin, especially around room temperature, is smaller than when no such thermoplastic elastomer is blended, so the temperature dependence of the pre-preda handleability is smaller. Therefore, it is preferable. Therefore, a pre-predder using this can exhibit excellent properties in tackiness, drapeability and quality. In order to obtain such an effect, it is preferable to blend 1 to 20 parts by weight of the polyester or polyamide elastomer with respect to 100 parts by weight of the thermosetting resin. The melting point of the polyester-based or polyamide-based thermoplastic elastomer is preferably 100 ° C. or more, and more preferably 140 ° C. or more, because it affects the heat resistance of the thermosetting resin composition after curing. It is preferably C or more.

Further, in order for a thermosetting resin composition containing a polyester-based or polyamide-based thermoplastic elastomer to obtain excellent physical properties of a composite material such as mechanical properties while maintaining excellent tackiness, a thermosetting resin composition is required. It is effective to incorporate a thermoplastic resin which can be thermodynamically dissolved in the curable resin, particularly a thermoplastic resin having a hydrogen bonding functional group. This is presumed to be due to the improved adhesion between the matrix resin and the reinforcing fibers.

It is preferable to add a thermoplastic resin as a modifier from the viewpoint that the decrease in the elastic modulus and the heat resistance is small as compared with the addition of a rubber or an elastomer. It is preferable to add a thermoplastic resin that dissolves in the thermosetting resin in an uncured state because the effect of improving toughness is greater than using thermoplastic resin fine particles that do not dissolve during resin preparation or molding. In particular, it is more preferable to select a combination of a thermosetting resin and a thermoplastic resin that forms a Miku mouth phase separation structure in a curing process once the thermoplastic resin is dissolved, since the toughness improving effect is large. . Specific examples of such thermoplastic resin additives include polyvinyl formal, polyvinyl butyral, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polymethylmethacrylate, polyacrylamide, copolymerized nylon, and dimer acid-based polyamide. Is received. From the viewpoint that the heat resistance and the elastic modulus are less reduced and the effect of improving the toughness is large, it is more preferable to add a thermoplastic resin belonging to engineering plastics such as polysulfone, polyether sulfone, polyether imide, and polyamide. Also, It is preferable that these thermoplastic resins have reactivity with the thermosetting resin from the viewpoint of improving the toughness and maintaining the environmental resistance of the cured resin. As particularly preferred functional groups, a hydroxyl group, an amino group, a hydroxyl group and the like can be used.

The thermosetting resin composition of the present invention may contain, in addition to the above additives, other additives such as a polymer compound, a reactive diluent, a chain extender, and an antioxidant. As the polymer compound, a compound soluble in an epoxy resin for various purposes can be blended. Specifically, reactive silicones and the like described in European Patent No. 475611 (corresponding Japanese Patent Application Laid-Open No. 6-93103) improve the toughness and ductility of the cured resin, It is effective and preferable for adjusting the fluidity of the product.

As the reactive diluent, a monofunctional epoxy compound is preferably used. Specifically, butyldaricidyl ether, 2-ethylhexylglycidyl ether, phenyldaricidyl ether, cresylglycidylether, P-sec-butyldaricidyl ether, P-tert-butyldaricidylether, etc. No.

Bisphenols are preferably used as the chain extender. Specific examples include bisphenol eight, bisphenol S, and fluorene bisphenol. By using a chain extender, it is possible to obtain a pre-preparer for a honeycomb sandwich panel having more excellent self-adhesiveness.

Antioxidants include phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol (BHT), butylated hydroxyanisole, and tocophenol, dilauryl 3,3'-thiodipropionate, Sulfur-based antioxidants such as distearyl 3,3'-thiodibution pionate are preferably used.

The thermosetting resin composition according to the present invention is a thermosetting resin composition having a fracture toughness value K _1C after curing of 1.OMP am ^1/2 or more measured according to ASTM D 5045-91. Is particularly preferred.

The use of a thermosetting resin composition with a fracture toughness value K _1C of 1. OMP a · m ^1/2 or more after curing makes it possible to evaluate the self-adhesion of honeycomb sandwich panels as cured molded articles. destruction progress under peeling stress is suppressed, climbing Dora Mupiru test (Nomex honeycomb SAH1 / 8-8.0 use, fiber basis weight 190 g / m ^2, the resin content of 44% carbon fiber reinforced Puripureda as the upper and lower honeycomb core (± 4 5 °) / (± 45 °) when two layers are symmetrically laminated). It is preferable that the fracture toughness value K _1C is 1.2 MPa · m ^1/2 or more to obtain a higher climbing drum peel strength, and further, the fracture toughness value K _1C is 1.5 MPa a * m ^1/2 or more. It is preferred that

Specific methods for obtaining a thermosetting resin composition having a fracture toughness value K _1C after curing of 1. OMP a · πι ^1/2 or more in the present invention include, for example, the following methods. That is, a resin having a large molecular weight between functional groups serving as cross-linking points is used, a cross-linking density is reduced by adding a molecular chain extender, or a solid rubber, a liquid rubber, a thermoplastic elastomer, a thermoplastic It is preferable to add an additive selected from resins. In particular, it is preferable to add a thermoplastic resin from the viewpoint of achieving both the heat resistance and the effect of increasing the toughness. At that time, it is more preferable to select one that forms a microphase-separated structure during the curing process because the effect of improving toughness is large. The domain size of the phase separation structure (the phase separation structure period in the case of a biphase continuous structure) is preferably 10 m or less in order to obtain a composite material containing a high concentration of reinforcing fibers. To 0.1 m or more.

Specific examples of such thermoplastic resin additives include polyvinyl formal, polyvinyl butyral, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polymethyl methacrylate, polyacrylamide, copolymerized nylon, and dimer monoacid-based polyamide. In particular, it is more preferable to add a thermoplastic resin belonging to engineering plastics such as polysulfone, polyethersulfone, polyesterimide, and polyamide from the viewpoint that the heat resistance and the elastic modulus are less reduced and the effect of improving toughness is great. In addition, it is preferable that these thermoplastic resins have reactivity with the thermosetting resin from the viewpoint of improving toughness and maintaining environmental resistance of the cured resin. Particularly preferred functional groups include a carboxyl group, an amino group, a hydroxyl group and the like.

The number average molecular weight of the thermoplastic resin modifier is preferably 10,000 or more from the viewpoint of providing a high toughness effect when added in a small amount. However, even in the oligomer region having a number average molecular weight of 4,000 to 10,000, the increase in viscosity upon addition is small compared to the polymer, so that a large amount can be added, and the effect of increasing toughness may be large. Is more preferable. In particular, in the case of an oligomer having an engineering plastic structure with high heat resistance, the molecular weight of the oligomer region may be sufficient since addition of a large amount does not impair the heat resistance of the entire resin. A toughening effect is easily obtained.

[C] is resin fine particles.

By mixing and dispersing the resin fine particles [C] in a pre-preda made by combining a matrix resin mainly composed of a thermosetting resin as the [B] and a reinforced fiber fabric [A], the pre-preda becomes a honeycomb core. The self-adhesive strength between the skin panel and the honeycomb core obtained by cocure molding after pasting is greatly improved. Furthermore, by mixing and dispersing the resin fine particles [C], surprisingly, the temporal change of tackiness of the prepreg is suppressed, the surface smoothness of the molded skin panel is improved, and the internal porosity is reduced. It also has the effect of causing

In addition, it has been found that this effect is particularly remarkable when the woven fabric pre-prepder has a cover factor of 95% or more.

The presence of fine resin particles [C] and a high cover factor suppress the resin from sinking into the fibers, and contribute to maintaining the tackiness of the pre-preda and improving the surface smoothness of the skin panel.

The resin that is the material of the fine particles as the resin fine particles [C] has a carbon-carbon bond, an amide bond, an imide bond, an ester bond, an ether bond, a carbonate bond, a urethane bond, a thioether bond, a sulfone bond, and a carbonyl in the main chain. It is preferable that the thermoplastic resin has a bond selected from the bonds, but it may have a partially crosslinked structure. Further, it may be crystalline or amorphous. In particular, polyamides, polycarbonates, polyacetals, polyphenylene oxides, polyphenylene sulfides, polyarylates, polyethers, polyesters, polyamides, polyamides, polyamide imides, polyether imides, polysulfones, polyurethanes, polyether sulfones, polyethers Ketones have excellent heat resistance and toughness, and are suitable as resin fine particles [C]. Among them, polyamide is most preferable, and greatly improves the peel strength of the honeycomb core Z skin panel. Among polyamides, nylon 12, nylon 11 and nylon 6Z12 copolymer have particularly good adhesive strength. It is preferable because it gives a degree.

When the material of the resin fine particles [C] is selected, it is preferable that the elastic modulus of the material of the resin fine particles [C] is lower than the elastic modulus of the cured product of the thermosetting resin [B] because higher adhesive strength is obtained. In particular, the flexural modulus of the material [C] is preferably 2 Z 3 or less, more preferably 1/2 or less of the flexural modulus of the cured product of [B].

Even if the resin fine particles [C] are evenly distributed in the resin of the pre-preda, the effect of improving the adhesive strength between the skin panel and the honeycomb core, suppressing the change in tackiness of the pre-preda over time, and improving the smoothness of the skin panel surface Having. However, it is preferable to distribute the high concentration in the vicinity of the prepreg surface, that is, in the vicinity of the bonding surface with the honeycomb core after molding, because it has the effect of improving the bonding strength without reducing the rigidity and heat resistance of the skin panel. In addition, it is preferable that a high concentration is distributed near the surface of the skin panel because it has the effect of improving the surface smoothness without reducing the rigidity and heat resistance of the skin panel. The form of the resin fine particles [C] may be any of spherical, irregular particles, porous particles, and fibrous particles having a large aspect ratio. However, it is particularly preferable that the shape of the pre-preg is close to a true sphere because the pre-preg has an effect of suppressing a change in tack with time, a self-adhesive property, and a surface smoothness of a molded article.

When the resin fine particles [C] are thermoplastic resin fine particles, the size thereof is preferably in the range of 1 to 50 m. If the average primary particle size is less than 1 im, the effect of improving the adhesive strength between the skin panel and the 82 cam core is reduced.If the average primary particle size exceeds 50, the arrangement of the reinforcing fibers is disturbed, and the strength may be reduced or impregnation may be impaired. is there. More preferably, the particle size is in the range of 1 to 30 m.

Rubber fine particles are also used as resin fine particles [C].

For example, core Z-shell type rubber particles can be mentioned. The method disclosed in U.S. Pat. No. 4,419,496, European Patent No. 45,357, and JP-A-55-94917 is disclosed. It is manufactured by Commercially available Koano shell type rubber particles include, for example, Paraloid E XL 2655 (manufactured by Kureha Chemical Industry Co., Ltd.) TR 2122 (manufactured by Takeda Pharmaceutical Co., Ltd.), EXL—2611, EXL-3387 (Rohm & Haas). Crosslinked rubber particles are also preferable as the resin fine particles [C]. Commercially available crosslinked rubber particles include XER-71P and XER-91P (Nippon Synthetic Rubber Co., Ltd.) Manufactured). Rubber particles having a diameter of preferably 5 m or less, more preferably 1 or less are used. When the particle diameter is larger than 10 m, when the reinforcing fiber is impregnated with the matrix resin, the fine particles are not uniformly dispersed, and it is difficult to obtain a toughening effect. A particle diameter of 1 m or less is particularly preferable because a composite having a high reinforcing fiber content of 50% by volume or more does not disturb the fiber orientation and has a remarkable effect of improving peel strength.

The content of the resin fine particles [C] is preferably in the range of 2 to 15% in the cured resin made of [B] and [C]. If it is less than 2%, the effect of improving the adhesive strength between the skin panel Z honeycomb core is inferior, and if it exceeds 15%, the strength of the honeycomb sandwich panel may be reduced or resin impregnation may be defective.

It is preferable that the resin fine particles [C] have a functional group capable of reacting with the thermosetting resin [B] in order to improve self-adhesiveness. Preferred functional groups include an epoxy group, a carboxy group, a hydroxyl group and the like.

Evaluation of the morphology, size, and distribution state of the resin fine particles [C] is performed by microscopic observation. Although an optical microscope may be used, it is preferable to use a scanning electron microscope because high magnification observation is possible. Regarding the particle morphology and size, it is preferable to dissolve the matrix resin in the pre-preda with an appropriate solvent, filter out the particles without dissolving only the particles, and observe with a microscope. Therefore, although the type of solvent depends on the type of fine resin particles and the type of matrix resin used, chlorinated solvents such as methylene chloride and solvents such as acetone and methyl ethyl ketone can be considered. The content of the fine particles can be calculated from the weight of the fine particles thus filtered, the weight of the original pre-preda and the weight of the unresolved reinforcing fibers.

Regarding the distribution of the fine particles in the pre-predator, it is preferable to observe the polished surface after the resin is hardened little by little from a low temperature for about 3 weeks to 1 month so that the resin in the pre-predator does not flow. In order to clarify the distribution state of the material, it is more preferable to stain with osmium tetroxide / phosphotungstic acid or the like before observation to give a contrast.

As a method for producing a prepredder, there can be used a method of dissolving a matrix resin in a solvent to reduce the viscosity and impregnation, and a hot melt method (dry method) of reducing the viscosity of the resin by heating and impregnating the resin. The hot melt method uses reinforced fiber A method in which a precoated material is prepared by impregnating the resin by heating and pressing a film coated with a fiber and an epoxy resin composition on release paper or the like from both sides or one side, and controlling the resin content and the thickness of the prepredder. It is more preferable because it is easy to obtain, and it is easy to obtain a pre-preda with the highest cover factor by selecting the pressure and temperature at the time of resin impregnation, and to provide a pre-preda with little change over time in tackiness and improve the surface smoothness of the molded plate.

[D] is the honeycomb core.

As a honeycomb core, a nomex honeycomb core made of aramid paper impregnated with a phenol resin is particularly preferable because it can form a high-strength structure while being lightweight. A cell size in the range of 3 to 19 mm is generally used. Alternatively, an aluminum honeycomb, a glass fiber reinforced plastic (GFRP) honeycomb, a graphite honeycomb, a paper honeycomb, or the like may be used.

In order to manufacture a honeycomb sandwich panel, several pre-predas made of a reinforcing fiber and a matrix resin are laminated on both sides of the honeycomb core, and are molded by a method of adhering to the honeycomb core while curing the resin in the pre-preda. .

Examples of the method of forming a honeycomb sandwich panel include vacuum bag forming, autoclave forming using a vacuum bag, and press forming. However, in order to obtain a high-performance 82-cam sandwich panel, autoclave forming is performed. Is particularly preferred. On the other hand, press molding is more preferable in order to shorten the molding cycle and obtain high quality surface smoothness. In particular, when phenol resin is selected as the matrix resin, press molding is often used.

The self-adhesion between the skin panel of the honeycomb sandwich panel and the honeycomb core was evaluated using the climbing drum peel strength (CDP). The laminated structure of the woven pre-predator was a two-ply symmetrical lamination of (± 45 °) / (± 45 °) both above and below the honeycomb core. When epoxy resin was used as the matrix resin, the curing conditions were as follows: the temperature was raised to 180 ° C in 1.5 minutes, kept at the same temperature for 2 hours, and cured in an autoclave. At that time, first, a nylon bag over the laminate on an aluminum tool plate, placed in the autoclave while keeping the bag in a vacuum state, inside the bag at given pressure to 1. 5 k gZcm ² to the next Return the vacuum to normal pressure, Thereafter, the pressure was raised to 3 kg / cm ^{2 and} then the temperature was raised. When a phenol resin was used as the matrix resin, press molding was performed at 140 ° C. for 10 minutes at a pressure of 17 kgZcm ² . The method for measuring physical properties and the method for evaluating effects in the present invention were performed by the following methods.

[Cover factor]

First, using a stereomicroscope, for example, a Nikon Corporation stereomicroscope SMZ-10-1, a photograph is taken of the surface of the prepreg while applying light from the back side of the prepreg. As a result, the yarn portion is black and the weave portion is white, and the transmitted light pattern of the fabric is photographed. The light amount is set in a range that does not cause halation. Next, the obtained photograph is photographed by a CCD (charge coupled device) camera, the photographed image is converted into black and white digital data representing light and dark, stored in a memory, and analyzed by an image processing device. From the area S1 and the area S2 of the white part (texture part), calculate the following formula Cover-factor-1 (Cf). Do the same for 10 places on the same fabric, and use the simple average as the coverage factor.

Cf = [(Sl -S2) / Sl] x i 00

In the present invention, a personal image analysis system LA-525 manufactured by Pierce Co., Ltd. was used as the CCD camera and the image processing device. In addition, the digital data includes a middle part between black and white at the boundary between the yarn part (black part) and the texture part (white part). It is necessary to set a threshold value for discriminating this intermediate portion into a yarn portion and a weave portion. For this reason, a model with a true cover factor of 75% (a 6 mm wide black tape stuck on a transparent paper in a grid pattern vertically and horizontally so that the cover factor is 75%) was created as a model. However, standardization was performed so that it could be correctly recognized as a cover factor of 75%.

[Strand tensile strength]

It was measured based on JIS-R7601.

[Tensile modulus E]

It was measured based on JIS-R7601. [Destructive strain energy]

Using the tensile strength (σ: kgf / mm ² ) measured according to JIS-R7601 and the elastic modulus E, it is calculated based on the following formula: \ ¥ = σ ² 2 E.

[Hook drop value]

At a temperature of 23 ° (with a 60% humidity atmosphere, a carbon fiber bundle is suspended vertically, and the upper and lower 20 to 30 mm of a stainless steel wire with a diameter of 1 mm and a length of about 100 mm are bent. The weight is applied to the lower part, and the upper part is attached to the fiber bundle.

[Fracture toughness value after curing of thermosetting resin composition K _1C ]

It is measured based on ASTMD 5045-91, and is a value obtained by preparing a 6 mm thick test specimen of a cured resin and measuring by a three-point bending method with a notch.

[Evaluation of tackiness of pre-preda]

As an evaluation of the tackiness of the pre-preda, the peeling force was measured after the pre-preda was pressure-bonded to each other. This method has parameters for applied stress, speed, time, temperature, and humidity. Regarding the evaluation of tackiness in the examples of the present invention, measurement was carried out under the following conditions using "Instron" Model 4201 universal tester (manufactured by Instron Japan Co., Ltd.) as a measuring device.

Sample: 50 X 50 mm

Load speed: 1 mm / min

Bonding load: 0.12MPa

Load time: 5 ± 2 sec

Peeling speed: 10 mm / min

Environment: 25 ° C, 50% relative humidity

[Porosity in skin panel]

The porosity in the skin panel of the honeycomb formed body was quantified by the area method. From above, the fabric pre-preda is placed on the upper surface of the honeycomb core (± 45 °) / (0 ° / 90 °) Z (0 ° Z90 °) Z (0 ° Z90 °), and (0 ° 90 °) Z on the lower surface of the honeycomb core (0 ° Z90 °) / (± 45 °) Laminated under the above conditions, the pre-preda was directly adhered to the honeycomb core under the above conditions, and a micrograph was taken of the cross section of the cured product. Photographed at double magnification, a honeycomb molded body of about 26 cm in length and about 19 cm in width was cut in the width direction, and the value obtained by dividing the porosity area in the cross-section of the lower skin panel by the cross-sectional area of the skin panel The index was used. At this time, the porosity area was calculated by selecting the 25.4 mm length range with the highest porosity in the entire field of view of the cross-section observation.

[Surface smoothness of skin panel]

The surface smoothness of the honeycomb molded body skin panel was evaluated by a surface roughness meter after forming the panel by the following method.

First, a pre-preda was laminated on both sides of the honeycomb core in a configuration of (± 45 °) / (± 45 °) so as to be symmetrical with two plies on one side. The laminate of the honeycomb core and the prepreg was placed on an aluminum plate on which a fluororesin film was laid and molded. The surface smoothness of this honeycomb sandwich panel on the tool plate side is

The surface roughness was quantified by a surface roughness tester Surf Test 301. A length of 8 mm was evaluated with a stylus, and the difference between the average height of five points selected from the highest points and the average height of five points selected from the lowest points was determined. This was performed five times and the average value was determined.

[Climbing drum peel test]

Performed according to ASTM D1781. In the case of an epoxy resin matrix, Nomex honeycomb SAH 1 / 8-8.0 (manufactured by Showa Aircraft Co., Ltd .: SAH 1 / 8-8.0, thickness 12.) 7 mm). In the case of phenolic resin matrix, Nomex honeycomb SAH1Z8-3.0 (Showa Aircraft Co., Ltd .: SAH18-3.0, thickness 12.7 mm) was used. Hereinafter, the present invention will be described in detail with reference to examples.

Example 1

Bisphenol A type liquid epoxy (Yukaka Epoxy Ep 828)

45 parts by weight, Cresol nopolak solid epoxy (Sumitomo Chemical Industries, Ltd. E

5 CN 220) 25 parts by weight, carboxyl group-containing solid acrylonitrile rubber rubber (NIPOL 1072, manufactured by Zeon Corporation) 4 parts by weight, nylon 12 fine particles 16 parts by weight (SP-500, manufactured by Toray Industries, Inc., average particle size 5 ^ m) were kneaded with a kneader. Further, 30 parts by weight of tetraglycidyldiaminodiphenylmethane (ELM434 manufactured by Sumitomo Chemical Co., Ltd.) and 3 parts by weight of fine-particle silica surface-treated with a trimethylsilyl group (Aerosil R812, manufactured by Dedasa) were added and kneaded. 38 parts by weight of 4,4'-diaminodiphenylsulfone as a hardening agent is added thereto, and

The mixture was stirred for 30 minutes to prepare an epoxy resin composition. When the resin was cured and the fracture toughness was measured, it was 1.5 MPa * m1 ^{/ 2} . The Tg of the cured resin was 214 ° C. By the way, the resin excluding nylon 12 fine particles was cured and the elastic modulus was measured.

45 OMPa. The modulus of elasticity of nylon 12 was 108 OMPa.

The resin composition was coated on release paper to prepare a resin film having a resin weight of 66 gZm ² . This resin film is set on a pre-predator machine, and the strand has a tensile strength of 4.9 GPa, a tensile strength of 230 &? _& , A tensile elongation at break of 2.1%, and a hook drop value of 170 mm. Carbon fiber plain woven fabric made of carbon fiber T 700 S C-12K (12000 fibers, fineness 7200 denier) (basis weight 190 g / m ² , yarn thickness 0. l lmm, yarn width yarn thickness ratio 70. 2 ) Was impregnated with resin from both sides to obtain a prepredder. The impregnation temperature at this time was 100 ° C. The cover factor of the prepared pre-preda was 99.2%. The tackiness of the prepreg before lamination and molding was measured and found to be 0.15 MPa. The tackiness after leaving this same prepreg in an environment of 25 ° C and a relative humidity of 50% for 10 days was 0.12 MPa, and the change with time was small. The drape property of the pre-preda was good.

The laminate of the honeycomb core and the prepreg was placed on an aluminum plate covered with a fluororesin film, and the laminate was vacuum-packed with a nylon film and subjected to autoclave molding. No adhesive film was sandwiched between the pre-preda and the honeycomb core, and the pre-preda was directly bonded to the honeycomb core while curing. The thus obtained honeycomb sandwich panel was subjected to a climbing drum peel test in accordance with ASTM D1781, and showed a peel strength of 15.4 lb · inch / 3 inch width.

To determine the porosity content in the lower skin panel, The cross section was polished with sandpaper and alumina powder, and an optical microscope photograph was taken. From this picture, the porosity was as low as 0.04%. The surface roughness of the tool side of the honeycomb panel was measured to be 3.8 xm, which was excellent. After the osmium tetroxide staining of the panel, reflection electron image observation with a scanning electron microscope was carried out. As a result, it was confirmed that a large number of spherical spherical nickel particles were uniformly distributed in the resin rich portion of the skin panel. Comparative Example 1

A resin composition was prepared in the same manner as in Example 1 except that nylon 12 fine particles were not added. Measurement of the fracture toughness to cure the resin 0. 7MP a - was ^l ^2. Next, a pre-preda was obtained in the same manner as in Example 1. The coverage factor of the pre-preda was 99.4%. When the tackiness of the pre-preda was measured, it was 0.14 MPa. The tackiness after leaving this same pre-preda for 10 days in an environment at 25 ° C and a relative humidity of 50% was 0.07 MPa, and the change with time was large. A honeycomb drum sandwich panel obtained by the same method as in Example 1 was subjected to a climbing drum peel test and found to have a peeling strength of 9.8 lb · inch 3 inch width. The porosity in the lower skin panel was 0.21%. The measured surface roughness was 15.4 m. Comparative Example 2

A pre-preda was obtained in the same manner as in Example 1, except that the impregnation temperature at the time of preparing the pre-preda was 6 Ot. The pre-preda cover factor was 94.4%. When the tackiness of the pre-preda was measured, it was 0.15 MPa. The tackiness after leaving this same pre-preda for 10 days in an environment at 25 ° C and a relative humidity of 50% was 0.08 MPa, and the change with time was large. When a climbing drum peel test was performed on the honeycomb sandwich panel obtained in the same manner as in Example 1, the peel strength was 12.4 lb · inch / 3 inch width. The porosity in the lower skin panel was 0.18%. The measured surface roughness was 14.9 im. Example 2

Bisphenol F type liquid epoxy (Epc830, Dainippon Ink and Chemicals, Inc.) 35 parts by weight, brominated bisphenol A type solid epoxy (Epcl52, Dainippon Ink and Chemicals, Inc.) 3 5 parts by weight, carboxyl group-containing solid acrylonitrile butadiene rubber (NIP OL 1472 HV manufactured by Zeon Chemical Co., Ltd.) 5 parts by weight, nylon 11 fine particles D-30 (Nippon Rilsan Co., Ltd., average particle diameter 30 m) 16 weight Parts were kneaded 2-1. Further, 30 parts by weight of tetraglycidyldiaminodiphenylmethane (ELM434 manufactured by Sumitomo Chemical Co., Ltd.) and 4 parts by weight of fine particle silica surface-treated with a dimethylsilicon group (Aerosil RY200 manufactured by Nippon Aerosil Co., Ltd.) were added and kneaded. Here, 40 parts by weight of 4,4′-diaminodiphenyl sulfone was added as a curing agent, and the mixture was stirred at 60 ° C. for 30 minutes to prepare an epoxy resin composition. When the resin was cured and the fracture toughness was measured, it was 1.3 MPa · m ^1/2 . The Tg of the cured resin was 203 ° C. Incidentally, when the resin excluding the nylon 11 fine particles was hardened and the elastic modulus was measured, it was 347 OMPa. The elastic modulus of nylon 11 was 990 MPa.

The resin composition was coated on release paper at 70 to prepare a resin film having a resin basis weight of 66 gZm ² . This resin film was set in a pre-preda machine, and impregnated with resin from both sides of a carbon fiber plain woven fabric (basis weight: 190 gZm ² ) consisting of Toray's carbon fiber T 700 S-12K as in Example 1. A prepredder was obtained. The impregnation temperature at this time was 100 ° C. Pre-Preda's cover factor was 97.9%. When the tackiness of the pre-preda was measured, it was 0.16 MPa. After leaving the same pre-preda in an environment at 25 ° C and a relative humidity of 50% for 10 days, the evening-life was 0.13 MPa and the change with time was small. The drapability of the pre-preda was good.

Honeycomb sandwich panel obtained by the same method as in Example 1

A climbing drum peel test according to D 1 781 showed a peel strength of 13.4 pound-inch / 3-inch width.

The porosity in the lower skin panel was as low as 0.08%. Also, honeycomb When the surface roughness of the sandwich panel on the tool side was measured, it was 7.9 m. After osmium tetroxide staining of the panel, reflection electron image observation with a scanning electron microscope was performed, and it was confirmed that amorphous nylon fine particles were uniformly distributed in the resin rich portion of the skin panel. Example 3

Bisphenol A-type liquid epoxy (Ep 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 189) 40 parts by weight, bisphenol A-type solid epoxy (Ep1001, manufactured by Yuka Shell Epoxy Co., Ltd.) Epoxy equivalent 467) 30 parts by weight, solid acrylonitrile butadiene rubber containing carboxyl group (NIP OL 1072, manufactured by Zeon Corporation) 5 parts by weight, nylon 12 fine particles (SP-500, manufactured by Toray Industries, Inc., average particle size 5) ^ m) 16 parts by weight were kneaded with a kneader. 30 parts by weight of tetraglycidyldiaminodiphenylmethane (ELM434 manufactured by Sumitomo Chemical Co., Ltd.) and 6 parts by weight of fine particle silica surface-treated with a trimethylsilyl group (Aerosil R812 manufactured by Dedasa) were added and kneaded. Further, 40 parts by weight of 4,4′-diaminodiphenyl sulfone was added as a curing agent, and the mixture was stirred at 60 ° C. for 30 minutes to prepare an epoxy resin composition. When the resin was cured and the fracture toughness was measured, it was 1.7 MPa · m ^1/2 . The Tg of the cured resin was 191 ° C. Incidentally, when the resin excluding the nylon 12 fine particles was cured and the elastic modulus was measured, it was 332 OMPa. The modulus of elasticity of nylon 12 was 1,080 MPa.

The resin composition was coated at 65 ° C on release paper, resin basis weight to prepare a resin film of 66 _§ 111 ^2. This resin film was set on a pre-preda machine and impregnated with resin from both sides of a carbon fiber plain woven fabric (basis weight: 190 gZm ² ) made of Toray's carbon fiber T700SC-12K, as in Example 1. I got a pre-preda. The impregnation temperature at this time was 100 ° C. The cover factor of the prepared pre-preda was 99.6%. When the tackiness of the pre-preda was measured, it was 0.14 MPa. The tackiness after leaving the same pre-preda in an environment at 25 ° C and a relative humidity of 50% for 10 days was 0.12 MPa, and the change with time was small. The prepreg had good drapability. The honeycomb sandwich panel obtained by the same method as in Example 1 was subjected to a climbing drum peel test in accordance with ASTM D1781, and showed a peel strength of 19.1 bond-inch 3 inches wide.

The porosity in the lower skin panel was as low as 0.02%. The surface roughness of the tool side of the honeycomb sandwich panel was measured and found to be 3.8 zm, which was excellent. After osmium tetroxide staining of the panel, reflection electron image observation was performed with a scanning electron microscope.As a result, it was confirmed that a large number of spherical spherical particles were uniformly distributed in the resin rich portion of the skin panel. Was. Example 4

A resin composition was prepared in the same manner as in Example 3, except that the nylon 12 fine particles SP-500 was replaced with nylon 6 12 copolymer fine particles Olgasol 3202D (Atochem Co., Ltd.). Orgasol was a porous particle with an average particle diameter of 20 m. Next, a prepredder and a honeycomb sandwich panel were obtained in the same manner as in Example 3. Pre-Preda's cover factor was 99.1%. When the tackiness of the pre-preda was measured, it was 0.13 MPa. After the same pre-preda was left in an environment of 25 and a relative humidity of 50% for 10 days, the tackiness was 0.1 IMPa and the change with time was small. The drape property of the prepredder was good. When the resin was cured and the fracture toughness was measured, it was 1.5 MPa · m ^1/2 . The Tg of the cured resin was 190. Incidentally, when the resin excluding the nylon 6/12 fine particles was hardened and the elastic modulus was measured, it was 332 OMPa. The refractive index of nylon 612 was 1610 MPa. When a climbing drum peel test was performed on the honeycomb sandwich panel, the peel strength was 18.2 lb · inch / 3 inch width. The porosity in the lower skin panel was 0.07%. The measured surface smoothness was 6.1 m. The panel was stained with osmium tetroxide and observed by backscattering electron microscopy using a scanning electron microscope. As a result, the presence of a large number of highly uneven nylon fine particles was observed in the resin rich portion of the skin panel. Example 5

A resin composition was prepared in the same manner as in Example 3 except that nylon 12 fine particles SP-500 was replaced with nylon 6 fine particles Orgasol 1002D (Atochem Co., Ltd.). Orgasol was a porous particle having an average particle diameter of 20 m. Next, a prepredder and a honeycomb sandwich panel were obtained in the same manner as in Example 3. The coverage factor of Prepreda was 99.3%. When the tackiness of the pre-preda was measured, it was 0.16 MPa. After the same pre-preda was left in an environment at 25 ° C and a relative humidity of 50% for 10 days, the tackiness was 0.12 MPa and the change with time was small. The drape property of the prepredder was good. When the resin was cured and the fracture toughness was measured, it was 1.3 MPa · m ^1/2 . The Tg of the cured resin was 192. Incidentally, when the resin excluding the nylon 6 fine particles was cured and the elastic modulus was measured, it was 3320 MPa. The elastic modulus of nylon 6 was 280 OMPa. When a climbing drum peel test was performed on the honeycomb sandwich panel, the peel strength was 14.2 lb · inch 3 inches wide. The porosity in the lower skin panel was 0.11%. The measured surface smoothness was 8.7 m. After the panel was stained with osmium tetroxide, a backscattered electron image was observed with a scanning electron microscope. As a result, the presence of a large number of fine particles with a lot of irregularities was confirmed in the resin rich portion of the skin panel. Example 6

Toray carbon fiber T300 with a strand tensile strength of 3.53 GPa, tensile modulus of elasticity of 230 GPa, tensile elongation at break of 1.5% and hook drop value of 160 mm. 3 K (number 30 00 present fiber, fineness 1 80 0 denier) other that a carbon fiber維平woven fabrics made of (basis weight 1 9 3 gZm ^2, Itoatsumi 0. 1 3 mm, the yarn width Itoatsumi ratio 1 2.1) In the same manner as in Example 1, a prepredder was obtained. The pre-predator cover factor was 96.4%. The tackiness of the pre-preda was measured and found to be 0.15 MPa. The tackiness after leaving the same pre-preda for 25 days in an environment of 25: relative humidity of 50% was 0.1 OMPa. In addition, the drainage of the prepred was good. The honeycomb sandwich panel obtained by the same method as in Example 1 was subjected to a climbing drum peel test according to ASTM D1781, and showed a peel strength of 14.1 bond-inch to 3-inch width.

The porosity in the lower skin panel was 0.11%. Also, the surface roughness of the tool side of the honeycomb sandwich panel was measured to be 8.6 m. After the panel was stained with osmium tetroxide, a reflection electron image was observed with a scanning electron microscope. As a result, it was confirmed that a large number of spherical spherical nylon particles were uniformly distributed in the resin rich portion of the skin panel. Example 7

Bisphenol A type solid epoxy (Epl OO 1, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 46 7) 45 parts by weight, bisphenol A type liquid epoxy (Euka Shell Epoxy Co., Ltd. Ep 828, Epoxy equivalent 1 89 9) 30 parts by weight, tetraglycidyldiaminodiphenylmethane (Sumitomo Chemical Co., Ltd. ELM434)

25 parts by weight, hydroxyl-terminated polyether sulfone (5003P, Mitsui Toatsu Co., Ltd.)

30 parts by weight were added and the mixture was kneaded in a mixer at 130 ° C. for 2 hours. Here, 12 parts by weight of nylon 12 fine particles (SP-500, manufactured by Toray Industries, Inc., average particle diameter: 5 zm) and 25 parts by weight of 4,4′-diaminodiphenylsulfone as a hardener were added, and the mixture was added at 60 °. The mixture was stirred at C for 30 minutes to prepare an epoxy resin composition. When the resin was cured and the fracture toughness was measured, it was 1.8 MPa · m1 / ² . The Tg of the cured resin was 178 ° C. Scanning electron microscopy of the fracture surface of the cured resin confirmed the presence of a microphase-separated structure having a domain with an average particle size of about 3 m.

The resin composition was coated on release paper to prepare a resin film having a resin weight of 66 g / m ² . This resin film was set on a pre-prepared machine, and the strand tensile strength was 4.9 GPa, the tensile modulus was 230 &? &, The tensile elongation at break was 2.1%, and the hook drop value was 170 mm. Co., Ltd. Carbon fiber plain woven fabric made of carbon fiber T 7 0 0 S C- 12 K (number of fibers 1 2 000, fineness 7 2 0 denier) (basis weight 1900 g / m Yarn thickness 0. ll The resin was impregnated from both sides with a mm and a yarn width / yarn thickness ratio of 70.2) to obtain a prepreg. The impregnation temperature at this time was 100 ° C. Made The pre-predator's cover factor was 98.3%. The tack and drape properties of the prepreg were good.

The laminate of the honeycomb core and the pre-preda was placed on an aluminum plate covered with a fluororesin film, and the laminate was vacuum-packed with a nylon film and autoclaved. No adhesive film was sandwiched between the pre-preda and the honeycomb core, and the pre-preda was directly bonded to the honeycomb core while curing. The thus-obtained honeycomb sandwich panel was subjected to a climbing drum peel test in accordance with ASTM D1781, and showed a peel strength of 19.3 lb · inch / 3 inch width. Comparative Example 3

A resin composition was prepared in the same manner as in Example 7 except that no nylon 12 fine particles were added. When the fracture toughness was measured, it was 0.9 MPa · m ^1/2 . Then, a pre-preda was obtained in the same manner as in Example 1. Pre-Preda's coverfact Yuichi was 98.4%. A climbing drum peel test was performed on a honeycomb sun panel obtained in the same manner as in Example 1, and it was found that the peel strength was 8.8 pounds • inch inch 3 inches wide. Industrial applicability

According to the present invention, when a honeycomb sandwich panel is molded, the skin panel has excellent surface porosity, reduced pits, excellent smoothness, low internal porosity, excellent self-adhesiveness, and changes in tackiness over time. A less woven pre-preda is obtained.

Claims

The scope of the claims

1. A woven pre-preda comprising at least the following [A], [B], and [C] and having a coverage factor of 95% or more.

[A] Reinforced fiber fabric

[B] Thermosetting resin or thermosetting resin composition

[C] Resin fine particles

2. The prepreg according to claim 1, wherein [A] is a reinforced fiber woven fabric containing at least carbon fiber and Z or graphite fiber.

3. The woven fabric in which the reinforcing fiber multifilament yarn has a thickness of 0.05 to 0.2 mm and a yarn thickness ratio of 30 or more is [A]. 3. The woven pre-predator according to item 1.

4. The woven prepreg according to any one of claims 1 to 3, wherein [A] is a reinforcing fiber woven fabric made of carbon fiber yarn having a tensile modulus of 200 GPa or more.

5. The woven fabric pre-predder according to any one of claims 1 to 4, wherein the woven fabric in which the number of filaments of the reinforced multifilament yarn is 5,000 to 30,000 is [A].

6. carbon fiber multifilament yarns as yarn, fabric basis weight 1 00 to 320 gZ fabric Puripureda according to any one of claims 1 to 5, m ² and is woven, characterized in that the [A].

7. The woven pre-predder according to any one of claims 1 to 6, wherein [A] has a woven structure selected from a plain weave, a twill weave, an entangled weave, and a weave.

8. [B] is a thermosetting resin composition having a fracture toughness value K _1C after curing measured according to ASTM D 5045-91 of 1. OMP a · m ^1/2 or more. The woven pre-preda according to any one of claims 1 to 7.

9. The woven prepreg according to any one of claims 1 to 8, wherein [B] is a thermosetting resin composition having a glass transition temperature after curing of 16 O: or more.

10. The woven pre-preda according to any one of claims 1 to 9, wherein at least the epoxy resin and / or the phenol resin are contained as [B].

11. The woven pre-preda according to any one of claims 1 to 10, wherein a glycidyl ether type epoxy resin having an epoxy equivalent of at least 400 or more is contained as [B].

12. The prepreg according to any one of claims 1 to 11, wherein [B] is a thermosetting resin composition containing a thermoplastic resin.

13. The thermosetting resin composition according to claim 1, wherein [B] is a thermosetting resin composition containing at least one selected from polyamide, polyether, polyester, polyimide, and polysulfone. 3. The woven pre-predator according to item 1.

14. The prepreg according to any one of claims 1 to 13, wherein [B] is a thermosetting resin composition containing a rubber component.

15. The prepreg according to claim 14, wherein the rubber component is an acrylonitrile-butadiene copolymer rubber.

16. The prepreg according to any one of claims 1 to 15, wherein [C] is a thermoplastic resin fine particle.

17. The textile pre-preda according to any one of claims 1 to 16, wherein [C] is at least one resin fine particle selected from polyamide, polyether, polyester, polyimide, polysulfone, and polyurethane.

18. The woven pre-preda according to any one of claims 1 to 17, wherein the elastic modulus of the material [C] is lower than the elastic modulus of the material [B].

19. The woven pre-preda according to any one of claims 1 to 18, wherein [C] is thermoplastic resin fine particles, and the particle diameter thereof is 1 to 50 m.

20. The woven fabric according to any one of claims 1 to 19, wherein the content of [C] is in the range of 2 to 15% in the resin consisting of [B] and [C]. Pre-preg.

2 1. The content of [B] + [C] is in the range of 33 to 50% by weight based on the total weight of [A] + [B] + [C]. The woven pre-preda according to any one of the above.

22. An 82-cam sandwich panel comprising at least the following skin panels [A], [B], [C] and [D].

[A] Reinforced fiber fabric

[B] Thermosetting resin or thermosetting resin composition

[C] Resin fine particles

[D] Honeycomb core

23. The honeycomb sandwich panel according to claim 22, comprising any one of claims 2 to 21.

24. The honeycomb sandwich panel according to claim 22, wherein skin panels comprising [A], [B], and [C] are present on upper and lower surfaces of the honeycomb core [D].

25. The honeycomb sandwich panel according to claim 22, wherein [D] is a honeycomb core selected from an aramid honeycomb, an aluminum honeycomb, a paper honeycomb, a GF RP honeycomb, and a graphite honeycomb.